An Electrical Engineers Solution to Dust Collection

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Project by kinger posted 11-17-2014 04:00 PM 4796 views 13 times favorited 23 comments Add to Favorites Watch

I am fairly new to woodworking and like many of you have a small shop which for me is a one car garage that my wife very kindly lets me use for my hobby. As I have gotten more and more into the craft of woodworking and naturally started to acquire tools I recently found myself at the age old problem of dust collection. At the time I only had a Delta table saw so I decided to buy a Shop Vac from the big box store (blue variety) to use as my “dust collection” solution. It did its job OK but I had two issues with it….it was extremely loud and it was a pain to turn on and off each time I wanted to make a cut.

Doing a little research here on LJ and using my EE knowledge I came up with my own dust collection solution to address these two issues:

First was the noise. I found that many people with shop vacs had built an enclosure and padded the inside with noise dampening foam to cut the decibels down. This seemed to work for them but there was a concern with overheating the motor thus degrading the life of the vac. So what I did was build a “snorkle” for the shop vac which ported air from outside the enclosure directly to the intake for the motor cooling. So I built an enclosure out of 3/4” MDF and the noise dropped significantly.

Second was the fun part to me…..building a circuit to automatically turn on and off the shop vac. The end goal was to be able to walk up to a piece of machinery, make a cut, and have the shop vac turn on and off automatically. And since I knew I was going to be expanding my tool collection I wanted this same scenario to be true to a minimum of three tools. Skipping all the technical design and non-woodworking stuff this is what I came out with.

I have the ability to plug in three tools all of which will trigger the shop vac to turn on and off by sensing the current in the individual circuits. I can adjust the trigger sensitivity for each tool and can also adjust the lag time that the shop vac stays on once the power tool is turned off. The shop vac can be turn on separately via a side switch if I need to do a bit of shop cleaning. For the future I built in the ability to open and close blast gates depending on which tool was turned on but am still figuring out the mechanical parts (not a ME :) ). The system can switch up to a 1.5HP vac although I’d beef up the contactor to account for starting amps if that were the case. I used a 2×4 to make an enclosure and some plexi-glass to enclose the whole thing.

Works great and i’m very pleased. Thanks for looking!

23 comments so far

View calisdad's profile


334 posts in 1683 days

#1 posted 11-17-2014 04:26 PM

Excellent ! Can I borrow you for a weekend? ;-)

I like the delay feature.

-- Groveland, CA.

View stefang's profile


16058 posts in 3508 days

#2 posted 11-17-2014 06:15 PM

That is an excellent solution.

-- Mike, an American living in Norway.

View BigAl98's profile


172 posts in 3212 days

#3 posted 11-17-2014 06:16 PM

Nice wiring job too….do you have a pdf of the circuit? I are an engineer 2…

-- Al,New Jersey -To thine own self be true

View mcoyfrog's profile


4504 posts in 3768 days

#4 posted 11-17-2014 07:27 PM

WOW thats kewl

-- Wood and Glass they kick (well you know) Have a great day - Dug

View timbertailor's profile


1594 posts in 1598 days

#5 posted 11-17-2014 07:55 PM

Nice wiring job too….do you have a pdf of the circuit? I are an engineer 2…

- BigAl98


With notes for higher HP systems please!

-- Brad, Texas,

View woodchuckerNJ's profile


1296 posts in 1807 days

#6 posted 11-17-2014 09:54 PM

yea I have a very similar setup.
I don’t worry about leaving it on , when I close the gate it shuts. No timer necessary.
My cabinet is so quiet I can easily talk on the phone while standing near it.

if you look at my shop pics under workshop or here
you will see an aluminum box that has relays to turn on and off the vac from the gates.

-- Jeff NJ

View philz's profile


5 posts in 1460 days

#7 posted 11-17-2014 10:47 PM

Interesting idea – I like the see-through wiring box

View Belg1960's profile


1075 posts in 3239 days

#8 posted 11-17-2014 11:07 PM

Are you using small ct’s to sense the machine loads?

-- ***Pat*** Rookie woodworker looking for an education!!!

View cstrang's profile


1832 posts in 3342 days

#9 posted 11-18-2014 12:07 AM

Wanna swing by my shop and make something like this for me? Its practical and looks super cool on the wall… win win!

-- A hammer dangling from a wall will bang and sound like work when the wind blows the right way.

View Dallas's profile


3599 posts in 2661 days

#10 posted 11-18-2014 12:15 AM

And you didn’t make it electrostatic?

-- Improvise.... Adapt...... Overcome!

View Mean_Dean's profile


6890 posts in 3321 days

#11 posted 11-18-2014 12:58 AM

Looks like a great solution to our never-ending problem of dust collection!

-- Dean -- "Don't give up the ship -- fight her 'till she sinks!" Capt James Lawrence USN

View RPhillips's profile


1233 posts in 2010 days

#12 posted 11-18-2014 01:35 AM

lol… Looks like something my father-in-law would have made. Had his whole house wired with relay and such, to make it more efficient.

Nice work!

-- Rob - Indianapolis IN - Learning... one mistake at a time...

View ElChe's profile


630 posts in 1510 days

#13 posted 11-18-2014 02:52 AM

Is that the flux capacitor? Electricity works by magic. Clearly.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

View MT_Stringer's profile


3181 posts in 3404 days

#14 posted 11-18-2014 03:36 AM

That looks really slick.

Do you have a chip separator upstream of the shop vac? If not, pipe one up off to the side and your life will be a lot easier. I have a Dust Deputy upstream of the sa,e vac you have. I hardly ever have to check the bag or filter. Everything goes into the DD.

-- Handcrafted by Mike Henderson - Channelview, Texas

View Xanthoman's profile


7 posts in 1459 days

#15 posted 11-18-2014 03:43 AM

I’ll have to figure out a similar system when I build my little shop. I’ll have to pay good attention in my electro-mechanical classes…. (I’m going for ME, so EE is not my forte)

-- -'Tis easier to govern the populous if they do not hate you.

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